Charles dear-



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m ears an FFTQES GHARLES DEAR, OF LONDON, ENGLAND, ASSIGNOR TO THE MIBIS STEEL COMPANY LIMITED, OF LONDON, ENGLAND.

MANUFACTURE or STEEL.

No Drawing.

To all whom it may 0012061 12:

Be it known that 1, CHARLES DEAR, a sub ject of the King of England, residing in London, England, have invented certain new and useful Improvements in the Manufacture of Steel, of which the following is a specification.

This invention relates to the manufacture of steel and is of a process to give the steel a treatment whereby a better steel shall result than if the said treatment be not employed.

The present invention provides a process for the treatment of steel by which a freshlycast ingot is, before its interior is set solid, immersed in Water or in an aqueous solution and is kept submerged therein suiiiciently long to prevent recalescence of the ingot after it has been removed from the said liquid.

In a modified form of process according to this invention a freshly-cast ingot that has not cooled to a temperature so low as to entirely solidify the interior is immersed in Water or an aqueous solution and is kept submerged therein suificiently long to prevent recalescence after its removal from submersion, for example the ingot may be stripped from the mold or taken from the soaking pit and thus immersed.

Some of the advantages resulting from this invention may be obtained if an ingot above the temperature of recalescence, and before it has been rolled or has otherwise had its surface mechanically Worked, is im mersed in water or an aqueous solution and kept submerged long enough to prevent recalescence after it has been removed from the said liquid.

In any case the best results are obtained if the solution in which the ingot is immersed be one containing solutes, such as will upon the immersion of the ingot liberate hydrogen at the surface of contact of ingot with the solution.

"it will be understood, therefore, that by this iifilention an ingot may be plunged either directly the mold has been stripped from it, or alternatively after it has been in the soaking p it for some time, or again alternatively at anytime provided 1ts surface has not been mechanically worked, as for example by rolling, and if it be at a temperature above that of recalescence. are obtained if Specification of Letters Patent.

Fit-tented May 27, 1919.

Application filed December 30, 1916. Serial No. 139,910.

the ingot be plunged as soon as practicableafter the mold has been stripped from it and while'its interior is still fluid or semifiuid. The sudden contraction of the shell gives rise to a strong compressive action upon the contents of the ingot and it is to this that we attribute some of the beneficial results of the treatment. Other beneficial results follow from the production of hydrogen at the surface of contact of the in get with the solution; these results are best promoted by employing a solution containing materials which either themselves liberate or promote liberation of hydrogen under the conditions stated.

The beneficial results of the treatment are not confined, as might be expected, to a superficial layer of the material, but appear to penetrate so deeply into the ingot as to affect its whole mass. 0

'The duration of immersion in any case has to be such. that recalescence does not take place in the open air after the ingot has been removed from the liquid, before it is returned to the soaking pits, and if they are taken from the soaking pit to the bath by reason of insufiiciency of plant or other causes preventing their being treated direct from the molds, then they should be immersed at above a temperature of 800 C. WVhen thus treated from the soaking pit they should preferably be allowed first to cool slightly in such a way that the exterior is colder than the interior, as is the case with ingots direct from the mold.

The liquid of the bath should preferably be at a temperature of between 110 and 120 F. and there must be a suflicient quantity of the liquid to provide a thick layer all around the ingot.

It has heretofore been proposed to treat steel with gas, fluids, or solids in order to introduce hydrogen thereintoand such processes have been applied to high carbon and low carbon steel; it hasfurthermore been proposed to immerse billets in various liquid compounds but difficulty has arisen from cracking of the billets and other undesirable results. It is found that if the steel be taken in ingot form and treated by the process of this invention, it is in a form that is more favorable to such treatment than any heretofore employed and ingots can be treated containing 1.4% of carbon and the thus treated steel can be rolled without cracking.

Moreover, it is found that an ingot of 0.5% carbon steel treated according to this invention produces a steel approximately ashard as 0.7% carbon steel treated-in the formof billets.

The general effect of this process is to enhance the toughness of the steel and its ductility. The process is applicable, with advantageous results, to alloy steels, such, for

example, as nickel steel. 7

What Iclaim as my invention and desire to secure by Letters Patent is i 1, The process of making steel, comprising the steps of casting an ingot, stripping the mold therefrom While. the interior of thein got is still molten, submerging the strippedv ingot as quicklyaspossible and before its interior hass'et solid, completely beneath the surfaceof an aqueous bath andkeeping the ingot thus submerged long, enough to prevent it from, recalescing at its surface when removed from the bath.

2. The process of making steel comprising the steps of casting an ingot, stripping the mold from the ingot While the interior is still molten, placing the ingotin a soaking pit inwhich thetemperature is such as to prevent'theinterior of the ingot from setting quickly, removing the ingot from the soaking'pit before'the interior of the ingot has ceased to be fluid, then plunging the ingotin an aqueous bath to quickly solidify the metal and retaining the ingot in the bath long enough to cool it sufficiently to prevent it from recalescing in the open air When removed.

3. The process of making steel comprising the step of casting an ingot, stripping the mold therefrom as soon as the surface is hardened I sufficiently to permit it to I be stripped,,p1acing:the ingot in a soaking pit in which the temperature is sufiiciently 1 high to prevent the interior of the ingot from setting quickly, removing the ingot from the pit While the interior is still fluid, allowing the ingot tocool slightly to form a coolskin, then, plungingthe ingot, While its interior is still fluid into an aqueous bath to quickly solidify the metal. and retain it in the bath long enough to cool it sufliciently to prevent it from recalescing in theopen air when removed.

In testimony Whereof I have signed my name to this specification. 7

CHARLES DEAR Copies of this patent may be obtained for five cents each, by addressing the fGiimmissioner ofIPatents,

Washington, I C. 

